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The Brain Science of Poverty

Three different studies published in the last 18 months found that children living at or below the federal poverty level were at risk for reduced levels of brain gray matter, neural connectivity and other markers of neurological health. These changes are believed to put children and adolescents at an increased risk for behavior problems, difficulty learning and depression.

While these findings are disturbing, the researchers conducting these groundbreaking studies say they also offer a way forward.

“The developing brain is malleable, so we have every reason to believe that by changing children’s experiences, we can change brain development and their lives for the better,” says Kimberly Noble, MD, PhD. Noble, a professor of neuroscience and education at Columbia University, is a principal investigator on a study of family income, parental education and brain structure in children and adolescents.

One in five children nationwide, and in Colorado, live in poverty. Though the U.S. Census Bureau reported on Sept. 13 the largest annual percentage-point drop in poverty since 1999, including among children, childhood poverty remains a significant public health problem.

Statewide, children of color are disproportionately affected by poverty. Black and Hispanic children in Colorado are more than three times more likely to live in poverty than white children.

Where Science Meets Social Concern

The negative impacts of poverty on physical and mental health and success in school are well-known. Now science is helping us understand why.

Noble and her colleagues studied 1,099 individuals aged 3 to 20. They found that children from families with a total annual income of less than $25,000 had 6 percent less total surface area in parts of the brain responsible for language, reading and executive function than did children whose families earned more than $150,000. Researchers found differences not only in the areas of the brain that “do the cognitive heavy-lifting,” Noble says, but across the entire brain. As family income increased, so did children’s brain surface area for those living at the lowest income levels.

Seth Pollack, PhD, is a professor of psychology at the University of Wisconsin-Madison and a lead researcher, with colleagues at the University of Michigan and Duke University, on a study that found results similar to Noble’s team.

Pollack’s team analyzed brain scans of 389 individuals aged 4 to 22. They reported that the volume of gray matter was 3 to 4 percent lower than the norm in children living just above the federal poverty level. Gray matter volume was even less—8 to 10 percent lower than the norm—for children living below the federal poverty level. Children from low-income households scored, on average, 4 to 7 points lower on standardized tests than their more affluent peers.

From Poverty to Poor Health

These studies reinforce others demonstrating how social determinants of health, including income, can be associated with discernable—and often profound—physiological effects on the body.

In another recent study, researchers at Washington University in St. Louis released an analysis of brain scans of 105 children aged 7 to 12. They concluded that children who lived in poverty as preschoolers were more likely to be depressed at age 9 or 10. The poorer the children, the weaker the neural connectivity between key brain structures, the study found.

Areas of the brain appear visibly “vulnerable to the environmental circumstances of poverty, such as stress, limited stimulation, and nutrition,” Pollack and his colleagues noted in their study. This may lead to neurochemical changes in the brain, impaired immune systems and increased risk for a host of physical and mental health conditions.

Noble cautions that these findings reflect population-level data and not the impact of poverty on any individual child. In addition, results of the research to date imply correlation, not causality. In many cases, it is the correlates of poverty—rather than poverty itself—that may be the culprit.

Noble believes there are two main pathways by which poverty can impact brain development. The first is what she calls the “investment pathway,” which considers the differences in what money can buy, including everything from housing and nutrition to how many toys and books a child has. The second is the “family stress pathway,” which includes the impact of limited resources on parents’ mental health, family stability and the quality of relationships within the home, among other measures.

“Chronically inadequate financial resources put parents under constant stress, which may lead to neglect, negativity or simply lack of positive reinforcement,” says Paula Braveman, MD, MPH, director of the Center on Social Disparities in Health at the University of California, San Francisco. (Braveman is a past speaker from The Trust’s Health Equity Learning Series; her presentation can be watched online.)

“Neglect may have more toxic effects even than physical abuse,” she adds.

In like fashion, Pollack notes that not feeling safe and secure, not having shelter or not knowing where you next meal is coming from can lead to both physiological and psychological stress. Additionally, children who see that their family is different from others are negatively impacted by such “visible inequalities,” Pollack says.

To test the impact of various correlates of poverty on children’s brain development, Noble is part of a team of social and neuroscientists who are raising funds to conduct the first randomized clinical trial of poverty reduction. They are proposing sites in four U.S. cities: New York, Minneapolis, Omaha and New Orleans.

Beginning in the summer of 2017, they hope to enroll 1,000 low-income mothers and randomize them into two groups: one that receives a large financial supplement, and one that receives a more modest supplement. Over three years, researchers will assess family processes and biological measures, including a complete assessment of the children’s biological, emotional and brain development.

“Based on the outcomes, we may have some concrete policy recommendations,” Noble says.

Supporting Children and Families

Some experts say that interventions aimed at improving living and learning conditions for children who are poor may help reduce or even eliminate the risks associated with early adverse experiences.

“People may think that once a child has been poor, this limits their educational and health outcomes, but that’s false,” says Pollack. “The brain is robust.”

Social and educational policies aimed at creating affordable housing, supporting parents, reducing crime and increasing access to health care may help lessen risks associated with living in poverty. Pollack and his team are studying the impact of permanent housing at a young age. In many cities, housing subsidies are limited, and parents may be on a housing waitlist until their children are older, Pollack notes.

At least one previous study has shown positive health results of providing safe, stable housing. The U.S. Department of Housing and Urban Development’s Moving to Opportunity demonstration program enabled families to move from public, project-based housing to publicly funded, voucher-based housing in safer neighborhoods.

More than a decade later, researchers found improvements in participants’ physical and mental health, and youth were arrested less often for violent crime.

Pollack believes that talking about the impact of poverty in biological terms is bringing more people into important conversations about how to alleviate the effects of poverty on children—and lift them out of it.

“People may have different views about the solution, but they have a shared concern,” he says. “No one wants kids to not do well.”